Dengue, Dengvaxia and “Rainbow fish”

Dengue, Dengvaxia and “Rainbow fish”

The Department of Health (DOH) declared a National Dengue Alert on Monday, July 15, 2019 due to the alarming record of dengue cases all over the country. State of calamities due to Dengue were declared in the provinces of Palawan, Capiz, Iloilo, Antique and South Cotabato.

Dengue is the fastest growing vector-borne disease transmitted by day-biting Aedes Aegypti and Aedes Albopictus mosquitoes.

Based on the records of the Philippine National Disaster Risk Reduction and Management Council, at least 281 died from dengue with 59,993 reported cases from January 1, 2019 to July 28, 2019. Almost half of the casualties or 111 are from Region 6 (Central Visayas). Region 7 (Central Visayas) has 62 cases; Region 4A (CALABARZON) has 50; Region 8 (Eastern Visayas) has 24; Region 12 (SOCSARGEN) has 21; and, Region 4B (MIMAROPA) has 13.

In the Bicol Region, dengue incidence also reached an alarming level with a total of 3,631 cases and 37 deaths from January 1 to July 27 this year.

Seven more regions, including the Bicol Region, are on alert threshold meaning there is a potential epidemic that may happen.


But while this is happening, there is an ongoing debate as to whether or not the Dengvaxia vaccine should return. The recall of the vaccine happened when Atty Percida Acosta of the Public Attorney’s Office (PAO) sounded an alarm about the alleged deaths of children injected with Dengvaxia. The alarm came after Sanofi Pasteur, the producer of the vaccine, issued a statement on November 29, 2017 that Dengvaxia produces risks of more severe disease where the recipient of the vaccine had not had a previous dengue infection.

According to PAO, 142 people, mostly children, died after receiving Dengvaxia, and 3,281 more were hospitalized. This became the bases for the cases filed against former President Noynoy Aquino, former Health Secretary Janette Garin, and a number of others. The case is still being heard in court.


The increasing number of dengue-related deaths and cases, however, made the Malacanang reconsider returning Dengvaxia. Presidential Spokesperson Sal Panelo hinted this in a statement causing Acosta to worry. According to Acosta, returning Dengvaxia is simply abandoning the case against the officials of the previous administration.

Malacanang is still silent on Acosta’s position but there is a possibility that the Duterte Administration might leave the PAO Chief on her own. It should be noted that because of Acosta’s case against Dengvaxia, trust on all the government’s vaccination programs suffered a severe blow. In February 2019, for instance, a measles outbreak was declared because the parents feared the possible side effects and related this to Acosta’s claims. The measles outbreak has yet to be lifted even after President Rodrigo Duterte himself called on the Filipinos to trust vaccinations once more. Malacanang has also cashed out on media advertisements because Duterte’s bloggers could not anymore take out their rantings against Dengvaxia.


Part of the efforts of the DOH and the government in general is the information dissemination on the 4S strategy. This is as follows:

  • Search and destroy mosquito breeding places
  • Self-protective measures like wearing long sleeves and use of insect repellent
  • Seek early consultation on the first signs and symptoms of the disease
  • Say yes to fogging if there is an impending outbreak.

The “Rainbow Fish”

The strategy, however, is still insufficient as there may be breeding places that are beyond the capacity of the residents to address. These may include canals, rivers and lakes where water is not flowing.


Fortunately, there is a way to address this. The Bureau of Fish and Aquatic Resources (BFAR) in Bicol is offering the idea of using the “Rainbow Fish” or the “isdang kanal” or “kataba” in Tagalog, or mosquito fish. It’s scientific name is Gambusia affinis.

Gambusia affinis is a larvivorous fish and feeds on zoopankton, small insects and insect larvae, and detritus material. It was introduced by the Americans in 1900 to combat malaria as “rainbow fish” eats mosquito larvae at all stages of life.

As BFAR Bicol puts it, “Ang mosquitofish sarong prubadong “bio-predator” kan lamok nin huli ta an mga “kiti-kiti” an saindang primer na pagkakan. Bistado an mosquitofish sa pagiging “larvicidal fish” o parakakan kan lamok na nasa “larval” o “pupal” stage pa sana. Ini sarong matibay na klase nin sira na nabubuhay dawa sa mga kanal o salog o sa mga lugar na an tubig “stagnant” na pwedeng istaran kan mga lamok na possibleng magdara kan helang na dengue.”

A Promise with a Caution

But while the mosquito fish or “rainbow fish” or Gambusia affinis is a promising bioprotector against dengue, nothing is wrong to be always on the side of caution. Janitor fish, for example, was first introduced as a helpful fish to clean the algae and debris in aquariums but eventually became a pest when it was, intentionally or not, thrown in the Marikina River.

Gambusa affinis reproduces fast and introducing it may become harmful to the native aquatic population. It is also known to have aggressive behavior so it may kill or injure small fishes, and may even compete for food with the local fishes.


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